1. Field of the Invention
The present invention relates to a structure of touch display panel and, more particularly, to a high-accuracy OLED touch display panel structure of narrow border.
2. Description of Related Art
In recent year, the flat panel display industry has been rapidly developed, and many products have also been made in pursuit of light weight, thinness, small volume and fine image quality for developing several types of flat-panel displays to replace traditional cathode ray tube display (CRT). FIG. 1 schematically illustrates the types of known display panels. As shown in FIG. 1, the flat panel display includes liquid crystal display (LCD), plasma display panel (PDP), organic light emitting diode (OLED) display, field emission display (FED), and vacuum fluorescence display (VFD).
Among these types of flat panel displays, the organic light emitting diode display (OLED) technology is the one with great potential. OLED was first published by Eastman Kodak Co. in 1987. It has the features of thinness, light weight, self-illumination, low driving voltage, high efficiency, high contrast, high color saturation, fast response, flexibility, etc., and is therefore deemed as positively evaluated display technology following the TFT-LCD. In recent years, due to the development of mobile communications, digital products and digital televisions, the demand for high-quality full-color flat-panel displays is rapidly increased. The OLED display is provided with not only the advantages of LCD display including thinness, power-saving, and full-color display, but also the features of wide viewing angle, self-illumination, and fast response that are better than LCD.
FIG. 2 schematically illustrates the basic structure of prior OLED display. The OLED display 200 includes a cathode layer 210, an OLED layer 220, an anode layer 230, a thin film transistor layer 240, a lower substrate 250, and an upper substrate 260, wherein the OLED layer 220 further includes a hole transporting layer (HTL) 221, an emitting layer 223, and an electron transporting layer (ETL) 225.
The light-emitting principle of OLED is such that the electrons and electric holes are injected from the cathode layer 210 and the anode layer 230 respectively by applying electric field and, after the electric holes pass through the electric hole transport sub-layer 221 and electrons pass through the electron transport sub-layer 225, the electrons and electric holes enter the light-emitting layer 223 with fluorescent characteristics and then are combined to produce excited photons, which immediately release energy and return to the ground state. The released energy will generate different colors of light based on different luminescent materials, so as to cause OLED to emit light.
Modern consumer electronic apparatuses are typically equipped with touch panels for use as their input devices. According to different sensing manners, the touch panels can be classified into resistive type, capacitive type, acoustic type, optical type and other type.
The principle of touch panels is based on different sensing manners to detect a voltage, current, acoustic wave, or infrared to thereby detect the coordinates of touch points on a screen where a finger or other medium touches. For example, a resistive touch panel uses a potential difference between the upper and lower electrodes to compute the position of a pressed point for detecting the location of the touch point, and a capacitive touch panel uses a capacitance change generated in an electrostatic combination of the arranged transparent electrodes with a human body to generate a current or voltage for detecting touch coordinates.
With the widespread use of smart phones, the multi-touch technique is getting more and more important. Currently, the multi-touch is implemented by projected capacitive touch technique.
The projected capacitive touch technique makes use of two layers of indium tin oxide (ITO) to form a matrix of sensing units arranged in intersected columns and rows, so as to detect precise touch positions. The projected capacitive touch technique is based on capacitive sensing, wherein it designs plural etched ITO electrodes and adds plural sets of transparent conductor lines that are on different planes and vertical with each other to form X-axis and Y-axis driving lines. These conductor lines are all controlled by a controller for being sequentially scanned to detect capacitance changes that are sent to the controller.
FIG. 3 is a schematic diagram of a prior touch panel structure 300. On the prior touch panel structure 300, the sensing conductor lines 310, 320 are arranged in the second direction (Y-direction) and in the first direction (X-direction). When a touch sensing is being performed and the sensing conductor lines 320 have to transmit the sensed signals to the control circuit 331 on a flexible circuit board 330, a great amount of wires at the side of the panel 340 is required for connection to the flexible circuit board 330. Such a prior design increases the border width of the touch panel and thus is not suitable for the trend of narrow border.
Therefore, it is desirable to provide an improved touch panel device to mitigate and/or obviate the afore-mentioned problems.